The present invention relates generally to cutting instruments, and more particularly to surgical scalpels and other knives having retractable blades.
It is well known that existing surgical cutting implements provide a significant potential for harm to surgeons and support personnel. That is, with attention directed toward the patient, rapid handling of surgical instruments with exposed sharp edges occasionally leads to cuts and puncture wounds, and more often to loss of integrity of surgical gloves. With increasing risk of life-threatening infectious diseases, it is imperative that such risks be minimized.
Utility knives having retractable blades are well known. Of the manually-operated (as opposed to spring-actuated) variety, there appear to be five types. A screw-type of locking mechanism is described in U.S. Pat. No. 2,735,176 for "Veterinary Surgical Knife," which issued to William J. Costin on May 22, 1953. A surgical knife, which includes a hollow ground blade of surgical steel and a hollow handle into which the blade can be fully retracted for protection while the blade is not in use and from which the edged portion of the blade can be projected for use with the blade disposed substantially in longitudinal alignment with the handle, is illustrated. The locking mechanism taught includes a threaded pin attached to the blade which extends through a slot in the handle, and a knob which is threaded onto the pin for locking the blade in either an extended or withdrawn position. Two hands are required for successful operation of the Costin invention.
Surgical scalpels having protective sheaths, which are secured to the scalpel handle when the scalpel is in use, but slidable over the blade when the scalpel is not required, are described in U.S. Pat. No. 3,905,626, for "Disposable Surgical Scalpel," which issued to Arduino Riuli on Sep. 23, 1975, and in German Patent P 3722-899-4, for "Skalpell," which issued to T. Peters on Jan. 19, 1989.
Rectractable-bladed knives having leaf-spring loaded operating buttons attached to a slide which bears the cutting blade, and which engage notches in the knife handle when released by the operator, are described in U.S. Pat. No. 1,853,572 for "Pocket Knife," which issued to A. F. Dodson on Apr. 12, 1932, in U.S. Pat. No. 3,079,686 for "Handle Construction For Sliding Blade Knives," which issued to E. B. Christy on Mar. 5, 1953, and in U.S. Pat. No. 3,863,339 for "Retractable Blade Knife," which issued to Albert Reaney et al. on Feb. 4, 1975.
A variation on this design is where the leaf-spring formed from the knife blade slider itself, as described in U.S. Pat. No. 4,089,112, for "Adjustable Blade Knife," which issued to James L. Richards on May 16, 1978, and in U.S. Pat. No. 4,884,307 for "Pocket Tool," which issued to Ralph Flood On Dec. 5, 1989.
In U.S. Pat. No. 3,879,847 for "Cutter With Forwardly And Rearwardly Displaceable Blade," which issued to Dieter Roll on Apr. 29, 1975, in U.S. Pat. No. 4,200,977 for "Cutter Knife," which issued to Toshihiko Kageyama et al. on May 6, 1980, and in U.S. Pat. No. 4,233,734 for "Retractable Blade Knife," which issued to Sylvester. W. Bles on Nov. 18 1980, cutting knives having operating members for locating the blade at any desired position outside of a hollowed handle portion adapted for shielding the blade when not in use, and means for securing the operating members at desired positions with respect to the handle portion by utilizing a series of engagement surfaces formed in the handle portion and located in a plane extending in a direction substantially perpendicular to the direction of movement of the operating member and a catch formed in the operating member, which releasible engages one of the engagement surfaces when the desired blade position is attained. In these inventions, a resilient, deformable operating member is employed in order to achieve the releasable engagement between the engagement surfaces of the handle and the catch in the operating member. Blade slides are designed and fabricated to accommodate the particular operating members and locking mechanisms employed, the blades themselves being attached to the blade slides, and handle portions are fabricated from more than one part in order to receive the complex operating members and blade slides,
Accordingly, it is an object of the present invention to provide surgical scalpels and other knives having retractable blades which may be locked in either a deployed or a retracted position,
Another object of our invention is to provide surgical scalpels and other knives having retractable blades which may be locked in either a deployed or a retracted position and which may be operated using one digit of one hand.
Yet another object of the invention is to provide surgical scalpels and other knives having retractable blades which may be locked in either a deployed or retracted position, but which cannot accidentally be deployed.
Still another object of our invention is to provide surgical scalpels and other knives having retractable blades for which standard, commercially-available blades are employed, and which have only three parts.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out, in the appended claims.